Gradient Bipolar Nanofiber Scaffolds with a Structure of Biomimetic Tendon-Bone Interface as Rotator Cuff Patches

Due to the special three-dimensional gradient structure from the bone to tendon at the tendon-bone interface (TBI), it is difficult to achieve a good therapeutic effect after rotator cuff injury. Biomimetic tissue-engineered gradient biphasic fiber patches may be a potential scaffold for repair. In this study, a gradient bipolar nanofiber scaffold with a structure of biomimetic TBI (SPGM) was prepared by continuous layer-by-layer electrospinning using poly(glycolide- co -ε-caprolactone), silk fibroin, and mesoporous bioactive glasses. The physicochemical characterization and mechanical test results confirmed that the SPGM could effectively avoid the stress concentration caused by easy to aggregate components and exhibited significantly matched mechanical properties. Moreover, SPGM also exhibited higher porosity, larger specific surface area, and suitable pore size for the growth of host cells. Cytocompatibility experiments, immunofluorescence staining, and cell morphology further demonstrated that the bipolar structure of gradient patches could induce rapid proliferation and adhesion of fibroblasts and osteoblasts, respectively. Therefore, this gradient bipolar nanofiber scaffold maybe a reliable candidate for rotator cuff repair.